He was held in jail. And beaten. On no charges. Without probable cause. You must be one of the police apologists that I keep reading about on FR. If that's the case, we're done.
The beating is (in principle) to subdue a hostile suspect, not as a punishment. If he wasn’t held for 24 hours, he wasn’t “held” in the Constitutional sense.
And if he doesn’t like it, he can sue.
He won’t, for the reason I detailed above.